Flexible intraocular implant injector

ABSTRACT

The invention relates to an injector device for injecting an intraocular implant into the eye of a patient, which device comprises a folding chamber for folding the optical portion of the implant, a folding member, a hollow needle for injecting the folded implant into the eye, said hollow needle opening out at a first end of said chamber, a guide channel opening out at the second end of said chamber, and a moving piston mounted in said guide channel so as to push said folded implant into said hollow needle. The piston ( 40 ) includes a cylindrical end ( 44 ) for co-operating with said implant, said end including an end face ( 50 ) that is substantially orthogonal to the length of the piston, said end face presenting an opening ( 52 ) opening out in the side wall of the end of the piston and extending over a portion only of the diameter of the piston, said end being provided with a slot ( 54 ) extending over a length l such that, together with the length of said opening, the total length is not less than the length of the haptic branch, said slot communicating with said opening and also extending over the entire diameter of the piston so as to open out at its diametral ends in the outside wall of the end of said piston.

PRIORITY CLAIM

This is a U.S. national stage of application Ser. No. PCT/FR01/02994,filed on Sep. 27, 2001. Priority is claimed from the followingapplication: Country: France, Application No.: 00 12349, Filed: Sep. 28,2000; the contents of which are incorporated herein by reference.

BACKGROUND OF TILE INVENTION

The present invention relates to an injector for injecting a flexibleintraocular implant, and in particular it relates to a piston for suchan injector.

Intraocular implants are vision-correction systems constituted by anoptical portion and by a haptic portion, the haptic portion serving tohold the implant in the eye in such a manner that its optical portionpresents an axis which coincides with the axis of the eye of the patientfitted with the implant. The implant is usually placed in the capsularbag of the eye once the natural lens has been removed, but it can alsobe put in place in the anterior chamber or in the posterior chamber ofthe eye of the patient.

In order to reduce the size of the incision required for putting theimplant into place inside the eye, intraocular implants have beendeveloped having an optical portion that is flexible and made ofsilicone or hydrophilic or hydrophobic acrylic materials. With suchimplants, it is possible to fold or to roll up the optical portion ofthe implant before inserting it into the eye, thereby enabling the totalsize of the implant to be reduced while it is being inserted into theeye.

The haptic portion of the implant has a purely mechanical function asexplained above, and it can be presented in various ways. In some cases,the haptic portion is constituted by two haptic elements also made of aflexible material, which can therefore be rolled up or folded togetherwith the optical portion. In other cases, the haptic portion can beconstituted by two haptic branches presenting regular curvature and madeof an intrinsically rigid material such as polymethylmethacrylate(PMMA), and having flexibility properties resulting from the smalltransverse size of the branches.

In order to assist the surgeon while the implant is being put into placein the eye, devices called intraocular-implant injectors have beendeveloped which fulfill the dual function of rolling up or folding theimplant and of inserting the folded implant into the eye by means of ahollow tube inserted through the incision made in the cornea of the eye.

SUMMARY OF THE INVENTION

FIG. 6 shows an embodiment of such an implant injector. It comprises abody 10 which defines a folding chamber 12 that is extended at one ofits ends by a hollow needle 14 and at its other end by a guide channel16 for a moving piston 18. In this embodiment, the folding chamber 12essentially comprises a folding wall 20 of semi-cylindrical shape and aplane surface 22 for receiving the implant. The injector also comprisesa moving folding-pusher 24 which, in this particular case, is mounted topivot about an axis X–X′ by means of an arm 26. The pusher 24 includes asemi-cylindrical active face 28 and a plane surface 30 parallel to theplane surface 22 of the rolling-up chamber. It should be understood thatwhen the implant I is disposed in the rolling-up chamber on the planesurface 22 by causing the pusher 24 to pivot about its axis X–X′, thesemi-cylindrical active face of the pusher co-operates with one of theedges of the implant I which is sandwiched between the twosemi-cylindrical surfaces 20 and 28. The movement of the pusher causesthe implant to be rolled up until said implant is totally rolled up orfolded inside the cylindrical volume defined by the two semi-cylindricalsurfaces 20 and 28. Once the implant has been rolled up or folded, saidimplant can be pushed by means of the piston 18 into the hollow needle14 for insertion into the eye of the patient.

When the haptic elements are relatively thick and made, for example, offlexible material, and are therefore folded at the same time as theoptical portion, the haptic element in contact with the end of thepiston 18 presents sufficient strength to ensure that the action of thepiston on the haptic element does not damage the haptic element whilethe folded implant is being moved by the piston. In contrast, when thehaptic portion is constituted by two curved branches made of rigidmaterial and present a cross-section that is small, the action of theend of the piston 18 on the end of the haptic branch risks damaging thehaptic branch and therefore making the implant itself unusable.

An object of the present invention is to provide an injector device forinjecting an intraocular implant, and more particularly to provide apiston for such an injector, which piston is adapted to the case ofintraocular implants including haptic branches of limited strength andcan be used in an implant injector of the type described in connectionwith FIG. 6 or of another type in which the implant is folded or rolledup inside the injector before action of the piston enables the implantto be pushed in the folded state.

In order to achieve this object, the present invention provides aninjector device for injecting an intraocular implant into the eye of apatient, which implant comprises a flexible optical portion and twohaptic branches each having a first end connected to said opticalportion and a second end that is free, said device comprising a foldingchamber for folding the optical portion of the implant, a foldingmember, a hollow needle for injecting the folded implant into the eye,said hollow needle opening out at a first end of said chamber, a guidechannel opening out at the second end of said chamber, and a movingpiston mounted in said guide channel so as to push said folded implantinto said hollow needle. The injector device is characterized in thatsaid piston includes a cylindrical end for co-operating with saidimplant, said end including an end face that is substantially orthogonalto the length of the piston, said end face presenting an opening openingout in the side wall of the end of the piston and extending over aportion only of the diameter of the piston, said end being provided witha slot extending over a length l in the axial direction of the piston,said length l being such that, together with the length of said opening,the total length is not less than the length of the haptic branch, saidslot communicating with the opening and also extending over the entirediameter of the piston so as to open out at its diametral ends in theoutside wall of the end of said piston.

It should be understood that as a result of the presence of the openingin the end face of the piston and of the slot in the end of said piston,the haptic branch of the intraocular implant can be put in place throughthe opening and the slot, before the intraocular implant is folded.During the folding operation, the flexible optical portion is rolled upor folded and the haptic branch is elastically deformed so as to take ona shape that is close to a straight segment by being housed in theopening and in the slot of the piston. Thus, when the implant is to beinjected into the eye of the patient, the end face of the piston actsdirectly on the periphery of the folded optical portion withoutmechanically stressing the haptic loop.

BRIEF DESCRIPTION OF THE DRAWINGS

Other characteristics and advantages of the invention appear better onreading the following description of an embodiment of the invention,given by way of non-limiting example. The description refers to theaccompanying drawings, in which:

FIG. 1 is a perspective view of a piston for an implant injector of theinvention;

FIG. 2 is a perspective view of the end of the rod of the piston;

FIG. 3 is a longitudinal section view of the entire implant injectorfitted with the piston shown in FIG. 1;

FIG. 4 is a detail view showing the haptic branch of the intraocularimplant engaged in the opening and the slot in the end of the piston;

FIG. 5 is a fragmentary longitudinal section of the implant injectorshowing it after the rolling-up or folding stage; and

FIG. 6, already described, shows an embodiment of an intraocular-implantinjector.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG. 1 shows a piston 40 for an implant injector. The piston comprises acylindrical rod 42 terminated by an end 44. The piston also comprises athicker body 46 terminated by a surface 48 enabling the piston to bepushed into the body of the injector.

FIG. 2 shows the end 44 of the piston 40. Said end has an end face 50which is substantially disposed in a plane that is orthogonal to theaxis Y–Y′ of the piston. The end face 50 of the piston is provided withan opening 52, and the end of the piston is provided with a diametralslot 54.

FIG. 3 shows an entire injector of the kind described in connection withFIG. 6, but provided with a piston 40 as shown in FIGS. 1 and 2. Theinjector is of the type shown in FIG. 6. However, the injector couldnaturally be of a different type, providing the implant is folded orrolled up in the injector, and the piston acts on an edge of the foldedimplant. In this figure, it can be seen that the opening 52 is disposedin a diametral plane of the piston and extends in the diametraldirection over a length l that is less than the diameter of the piston,and that is preferably no more than about the radius of said piston. Ina particular embodiment, the piston has a diameter equal to 2 mm, theopening 52 in the end face has a length e of 0.5 mm in the diametraldirection. The slot 54 communicates with the opening 52 and extends overthe entire length of the diameter of the piston. As a result, bothdiametral ends 54 a and 54 b of the slot open out to the outside wall 40a of the piston. The opening 52 presents an axial length l′, and theslot 54 presents an axial length l. The lengths l′ and l are determinedin such a manner that their sum is not less than the length of thehaptic branch A of the intraocular implant I. The sum of the lengths canbe equal to 10 mm.

The opening 52 and the slot 54 preferably have the same width e′ insection on planes that are orthogonal to the axis Y–Y′ of the piston.Naturally, this width is greater than the thickness of the haptic branchof the implant. This width can be about 0.3 mm.

As can be seen better in FIG. 4, the end face 50 of the piston ispreferably not plane, but is constituted by a spherical cap 50 a of axisY–Y′, the spherical cap being concave.

This figure also shows that the diametral dimension eof the opening 52preferably increases progressively from the end face 50 to the slot 54.This disposition makes it easier to insert the branch of the implantinto the opening 52.

As a result of the fact that the opening 52 corresponds only to afraction of the diameter of the piston, the branch of the implantremains securely held in the opening 52 and the slot 54. Furthermore, itis the periphery of the end face 50 which bears on the periphery of theoptical portion of the implant.

As can be seen better in FIG. 3, the body 46 of the piston is preferablyprovided with temporary retention means, preferably temporary clip means60 which can co-operate with temporary retention means, preferablytemporary clip means 62 provided in the inside face 16 a of the guidechannel 16 of the implant injector. The temporary clip system enablesthe entire piston 40 to be temporarily prevented from moving intranslation, in a position such that the entire slot 54 at the end ofthe piston is disposed inside the rolling-up chamber 12 of theintraocular-implant injector. The piston 40 is shown in this position inFIG. 3. In this position, no mechanical stress is applied to the implantor to its haptic portion. In this position of the piston, the implantcan thus be stored inside the injector.

Operation of the injector shown in FIGS. 2 to 5 is described below. Withthe piston 40 in the position shown in FIG. 3 and held in said positionby means of the temporary clip system 60, 62, the pusher 24 of theinjector is fully extended, as shown in FIG. 6. The implant I is thusput in place on the plane surface 22 of the rolling-up chamber byengaging the free end A1 of the haptic branch A firstly in the opening52, and then in the slot 54. After this operation, the implant occupiesthe position shown in FIG. 3, and the free end A1 of the haptic loop Aprojects out of the slot 54.

FIG. 5 shows an implant injector when the pusher 24 is in its finalposition, in which the semi-cylindrical surfaces 20 and 28 define the“rolling-up chamber”, i.e. the optical portion B of the implant I isrolled up or folded, and the haptic loop A1, previously inserted intothe slot 54, is subjected to stress which causes it to deform so as tobring it into a substantially rectilinear position inside the slot 54and the opening 52, and the second haptic loop C is subjected to exactlythe same deformation.

It will be understood that in order to insert the folded implant intothe eye of the patient, it suffices to insert the hollow needle 14through the incision made in the cornea of the patient. The surgeon thendrives in the piston 16 causing the end face 50 of the piston to bearagainst the end of the rolled-up optical portion. The piston thus exertsno mechanical stress on the haptic loop A. This thrust enables theimplant to be moved into the hollow needle and to be inserted into theeye, in which the intraocular implant returns to its initial shape.

It should also be emphasized that the end face 50 of the piston ispreferably in the shape of a concave spherical cap. The periphery 50 bof the spherical cap thus forms an obtuse angle with the inside wall ofthe guide channel and of the rolling-up chamber. This prevents any riskof the end of the piston pinching the inside wall of the channel or ofthe rolling-up chamber when the piston is driven in.

1. An injector device for injecting an intraocular implant into the eyeof a patient, said implant comprising a flexible optical portion and twohaptic branches each having a first end connected to said opticalportion and a second end that is free, said device comprising: a foldingchamber for folding the optical portion of the implant, said chamberhaving a first and a second end, a folding member, a hollow needle forinjecting the folded implant into the eye, said hollow needle openingout at said first end of said chamber, a guide channel having an insidewall opening out at said second end of said chamber, and a moving pistonmounted in said guide channel so as to push said folded implant intosaid hollow needle, said piston having a longitudinal axis, said pistonincluding a cylindrical end for co-operating with said implant, said endincluding an end face substantially orthogonal to the length of thepiston and a side wall, said end face presenting an opening that opensout in said side wall of the end of the piston and extends over aportion of the diameter of said end of the piston, said portion beingless than the entire diameter of said end, said end being provided witha slot extending over a length in the axial direction of the piston,said slot length being such that, together with the length of saidopening, the total length is not less than the length of the hapticbranch, said slot communicating with said opening and also extendingover the entire diameter of said end of the piston so as to open out atits diametral ends in said outside wall of the end of said piston, saidslot and said opening having substantially the same width andsubstantially the same diametral median plane.
 2. A device according toclaim 1, wherein said end face is in the shape of a concave sphericalcap, having the same axis as said piston.
 3. A device according to claim1 wherein said piston and said inside wall of said guide channel includetemporary retention means for holding said piston in a position suchthat the entire slot of the piston is in said folding chamber.
 4. Adevice according to claim 1 wherein the dimension of said opening in thediametral direction of the piston, in said end face, is not greater thanthe radius of the piston.
 5. A device according to claim 1 wherein thedimension of said opening in the diametral direction of the pistonincreases progressively from said end face to said slot.